Time zone, Region, UTC picker

- Extract most common view related codes into BaseTimeZoneAdapter
  and BaseTimeZonePicker. Subclass handles the text formatting and
  order.
- Search view is added compared to previous version of time
  zone picker
- SpannableUtil is added to preserve spannable when formatting
  String resource.
- Fix the bug using GMT+<arabic> as time zone id. b/73132985
- Fix Talkback treating flags on screens as a separate element

Bug: 72146259
Bug: 73132985
Bug: 73952488
Test: mm RunSettingsRoboTests
Change-Id: I42c6ac369199c09d11e7f5cc4707358fa4780fed
(cherry picked from commit fbd30acef0)

src/com/android/settings/datetime/timezone/FixedOffsetPicker.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.datetime.timezone;
+
+import android.icu.util.TimeZone;
+
+import com.android.settings.R;
+import com.android.settings.datetime.timezone.model.TimeZoneData;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Date;
+import java.util.List;
+import java.util.Locale;
+
+/**
+ * Render a list of fixed offset time zone {@class TimeZoneInfo} into a list view.
+ */
+public class FixedOffsetPicker extends BaseTimeZoneInfoPicker {
+    /**
+     * Range of integer fixed UTC offsets shown in the pickers.
+     */
+    private static final int MIN_HOURS_OFFSET = -14;
+    private static final int MAX_HOURS_OFFSET = +12;
+
+    public FixedOffsetPicker() {
+        super(R.string.date_time_select_fixed_offset_time_zones,
+                R.string.search_settings, false, false);
+    }
+
+    @Override
+    public List<TimeZoneInfo> getAllTimeZoneInfos(TimeZoneData timeZoneData) {
+        return loadFixedOffsets();
+    }
+
+    /**
+     * Returns a {@link TimeZoneInfo} for each fixed offset time zone, such as UTC or GMT+4. The
+     * returned list will be sorted in a reasonable way for display.
+     */
+    private List<TimeZoneInfo> loadFixedOffsets() {
+        final TimeZoneInfo.Formatter formatter = new TimeZoneInfo.Formatter(getLocale(),
+                new Date());
+        final List<TimeZoneInfo> timeZoneInfos = new ArrayList<>();
+        timeZoneInfos.add(formatter.format(TimeZone.getFrozenTimeZone("Etc/UTC")));
+        for (int hoursOffset = MAX_HOURS_OFFSET; hoursOffset >= MIN_HOURS_OFFSET; --hoursOffset) {
+            if (hoursOffset == 0) {
+                // UTC is handled above, so don't add GMT +/-0 again.
+                continue;
+            }
+            final String id = String.format(Locale.US, "Etc/GMT%+d", hoursOffset);
+            timeZoneInfos.add(formatter.format(TimeZone.getFrozenTimeZone(id)));
+        }
+        return Collections.unmodifiableList(timeZoneInfos);
+    }
+}